What is the Origin of Hypothalamic-Pituitary-Liver Axis?

This conceptual framework is an extension of the classical hypothalamic-pituitary axes (HPA, HPG, HPT), acknowledging the liver's critical role as a major target and endocrine organ itself. The term axis signifies the bidirectional communication and feedback loops between these three distinct anatomical and functional components. Its recognition is a result of research into the endocrine control of somatic growth and metabolism.

What is the Mechanism of Hypothalamic-Pituitary-Liver Axis?

The hypothalamus releases Growth Hormone-Releasing Hormone (GHRH), which stimulates the anterior pituitary to secrete Growth Hormone (GH). GH then acts primarily on the liver, stimulating the synthesis and release of IGF-1, the main mediator of GH's anabolic effects. IGF-1, in turn, exerts negative feedback on both the pituitary and the hypothalamus, regulating the pulsatile release of GH and GHRH, thereby maintaining systemic growth and metabolic balance.

Hypothalamic-Pituitary-Liver Axis

Meaning

The Hypothalamic-Pituitary-Liver Axis (HPL axis) describes a complex neuroendocrine regulatory pathway involving the hypothalamus, the pituitary gland, and the liver, which collectively modulate a range of metabolic and growth-related functions. While less commonly discussed than the gonadal or adrenal axes, it is central to the control of Insulin-like Growth Factor 1 (IGF-1) production and overall metabolic homeostasis. Dysregulation in this axis is implicated in various growth disorders and metabolic diseases.